Data centers typically involve a large number of rack-mounted servers that are housed together in cabinets. Recent increases in processor speeds and reductions in the size of processors have meant that more processing power is provided by each server within a cabinet, and consequently the amount of power required to operate the server cabinets has increased dramatically. Additionally, power is typically needed for fans and other cooling equipment, due to the large amount of heat generated by the processors. A typical server cabinet in a data center contains 42 1U dual-power supply servers in each cabinet. Power demands for such a cabinet far exceed typical single-phase 120V 20 A power circuits, and thus three-phase power circuits must be used.
A problem arises when designing power supplies for server cabinets because the rated amperages of servers do not correlate with the amount of power that the device typically consumes. As an example, a device that is rated as 220 A, 220V and thus requires a power supply of 440 kW will typically not draw more than 2 kW. Most servers, and hence the cabinets that they are stacked within thus have a significantly overweighted power supply because the data center must dedicate the rated amount to the circuit.
It is desirable to be able to move the overweighting of the power supply circuit from each individual server to the cabinet itself. In this way, the distribution of power within the cabinet can be managed appropriately.